I should send this to my sister. She's a bit of a canary in a coalmine - she'll tell you to be careful with a knife because it's sharp and you could cut yourself. Thanks, Jo; that's why I'm using it.
But to be fair she's constantly sort-of-sick, and my father does actually have lupus, though i'm not sure of the form. It did take years of going to different medical professionals to get that diagnosis, and now he's doing a bit better. Chronic illness bites.